In the year of 1978 to 1979 the emphasis of EBV study will be: 1) process of EBV infection in various cell systems, 2) structural study of virus DNA, 3) status of plasmid virus DNA in cell chromatin. Raji cells which contain EBV genomes and BJA-B cells, free of EBV genomes, will be infected with HR1 virus and/or B95 virus and the extent of virus replication will be examined. TPA (tumor promotor) is now known to induce EBV from various cell lines which facilitate EBV production for virus DNA extraction. Various virus DNA, including NHA established from infectious mononucleosis, AG established from Burkitt's lymphoma as well as B95 and HR1 will be compared by restriction enzyme fragment pattern, physical mapping and electron microscope study (partial denaturation, self annealing and heteroduplex). Primate virus DNA fragments obtained by restriction enzymes will be examined which fragments share homology with EBV DNA fragments. Attempts to isolate virus specific chromatin in Raji cells will be continued. A possibility of the integration of a few virus genomes in Raji cells will be analyzed by Southern blotting hybridization of restriction enzymes fragments of total cell DNA with radioactive virus DNA probe. Relation of EBV with NPC tumor will be studied on Malaysia tumors. Characterization of virus specific m RNA in Raji cells will be continued in regard to size and specific localization of transcriptional region in virus DNA.